A tourist helicopter crash in New York City's East River that killed all five passengers was "survivable," but a secondary harness system likely preventing them from escaping, according to the National Transportation Safety Board.
In the final report from the NTSB, released on Friday, the agency said the decision by Liberty Helicopters Inc. and NYONair to use "locking carabiners and ineffective cutting tools as the primary means for passengers to rapidly release from the harness/tether system was inappropriate and unsafe."
The helicopter crashed March 11, 2018, into the river near Manhattan's Upper East Side. The crash happened when the tail of one of the front passenger's safety tethers got caught on the fuel shutoff lever during the flight, according to the NTSB.
The five passengers all drowned, according to the city's medical examiner. They were identified as Daniel Thompson, 34, and Tristian Hill, 29, both of New York; Trevor Cadigan, 26, Brian McDaniel, 26, both of Dallas; and Carla Vallejos-Blanco, 29, of Argentina.
The pilot, Richard Vance, was able to free himself from his harness and escape.
After the crash, questions arose over the harnesses and their effectiveness.
"The pilot knew what to do because he wears that harness every day," ABC News aviation expert Steve Ganyard told ABC News March 2018. "But these poor civilians out for a nice Sunday flight encountered something that was very, very difficult to survive."
The passengers all were wearing two harnesses, according to the NTSB -- one FAA-approved safety harness, and another issued by NYONair that tethered passengers to the helicopter to help prevent falling out of the doors-off flight.
The NTSB report said the Federal Aviation Administration's approval process for supplemental passenger restraint systems, which was implemented after the accident, is "inadequate" because it does not give inspectors guidance to evaluate the potential for entanglement or aircraft-specific installations.
Jerry Eisenband, the chief communications officer, told ABC News he could not comment on the report because the company's involved in active litigation.
The parents of Cadigan sued Vance, Liberty Helicopters and other operators in March 2018, claiming the defendants were negligent.